For cuts in thin materials with a sheet thickness up to several centimeters, due to the oscillations and the coarse movement of the saw chain, a motor saw (chain saw) can be guided safely only with an increased expenditure of force and attention.
When cutting thin materials such as, for example, a vapour barrier or a sheet wall, especially with carbide tipped saw chains, the user cannot see the space lying behind the cut and can thus run into dangerous situations or destroy the saw chain, particularly in the life-saving service (fire brigade, technical welfare organization etc.) due to the damage of lines or objects.
By deeply immerging rail points, third parties which are in the danger zone, can be endangered. This is valid for example when the fire brigade opens a flat roof for rescue parties which are in the space below.
In particular, the fire brigade thus wishes a depth limiter for motor saw works during the rescue service.
Different configurations of depth limiters for motor saws are already known by the prior art. So, for example the problem of the depth limitation of the motor saw type 046 HDR of the STIHL company is solved by a displaceable cover with a rounded front opening. Similar solutions are also known from U.S. Pat. No. 5,435,065, U.S. Pat. No. 5,156,156 and U.S. Pat. No. 4,833,781.
The disadvantage of these known depth limiters is the comparatively high construction expenses which simultaneously causes a considerable increase in weight of the saw as well as the sensitivity of the adjusting mechanism.
Thus, the aim of the invention is to create a chain saw with an adjustable depth limiter which has a comparatively light and simple construction, which is simple and safe to operate and which is characterized by its robustness when in service.
The aim is reached by the whole characteristics of claim 1. The heart of the invention is a lengthwise adjustable wheelset which is fixed to the rail of the chain saw with at least respectively one running wheel on both sides of the rail. In the proposed solution, the running wheels fixed on the left and on the right of the rail take over the function of the depth limitation and of the stop for absorbing the tensile forces developed by the saw chain.
The depth limiter according to the invention is particularly simple and robust if, according to a preferred configuration of the invention, a multitude of holes are placed the one behind the other in the longitudinal direction for adjusting the wheelset in the rail and if the wheelset is dismountable in several parts which can be connected the one with the other through one of the holes in such a way that the wheelset is fixed on the respective hole.
Preferably, the parts of the wheelset comprise a first flange situated parallel to the rail with a first wheel bearing for receiving the first running wheel and a second flange situated parallel to the rail for receiving the second running wheel. A bush which is perpendicular to the flange for passing through the hole in the rail is placed on one of the flanges, while the other flange has a corresponding bore hole for receiving the bush.
There results a quick and simple fixation of the wheelset on the rail when a collapsible bolt which can be put through both flanges is provided for connecting the parts, whereby this bolt can be tensioned by means of a tensioning device and which fixes when tensioned the wheelset on the rail, the tensioning device preferably comprising a manually actuatable eccentric clamp.
Further configurations of the chain saw according to the invention result from the dependent claims.